Disposable, single use, treatment cartridges having a rigid plastic exterior shell containing a treatment media for filtering or treating drinking water dispensed from a refrigerator door come in a wide variety of sizes and styles. Generally, the treatment cartridges are installed into a corresponding manifold located on an interior portion of the refrigerator. Once installed, the treatment cartridge remains in a fixed position and an electrical contact operating a solenoid actuating a water supply valve is used to dispense drinking water into a glass when depressing the electrical contact completing the circuit.